1. Field of the Invention
The present invention relates to a four poles mold cased circuit breaker, and more particularly, to a rotation pin correction mechanism for the four poles mold cased circuit breaker.
2. Description of the Conventional Art
Four poles mold cased circuit breaker is a mold cased circuit breaker capable of connecting an electric line of neutral pole (neutral phase) (hereinafter, abbreviated as “N” pole) as a ground pole in addition to the electric lines for three alternating currents having a phase difference, i.e. R, S, and T three poles (phases) in a mold cased circuit breaker.
In general, a mold cased circuit breaker is configured by accommodating a trip mechanism for detecting the generation of an abnormal current on a circuit in an enclosure with a synthetic resin material having electric insulation characteristics, a switching mechanism which provides means for an electric circuit to be manually switched by handle manipulation or can provide a driving force for automatic trip operation of the circuit through triggering by the trip mechanism, and an arc extinguishing mechanism for extinguishing an arc generated between contacts during trip operation.
Furthermore, typically, a mold cased circuit breaker may include a movable contactor and a stationary contactor provided with a contact, an arc extinguishing mechanism, and a trip mechanism for each pole.
Here, insulating partition walls are formed within the enclosure to electrically insulate between poles (in other words, between phases), thereby preventing a short circuit from being generated between the relevant mechanisms for each pole.
For recent mold cased circuit breakers, many manufacturers employ a method in which a so-called single pole unit is configured therein by accommodating the movable contactor and stationary contactor, arc extinguishing mechanism, and trip mechanism provided for each pole into insulating cases, respectively, separately from the enclosure to be sealed from the outside with intention to enhance productivity and convenience of maintenance by reinforcing electric insulation between the poles and promoting the modularization of mechanisms.
A four poles mold cased circuit breaker is provided with total four single pole units since the single pole unit is provided for each pole, and one switching mechanism for manually switching or trip-driving the relevant single pole units in common is provided at an upper portion of the single pole unit for the S pole (S phase) among the single pole units for R, S, T, and N poles.
Furthermore, a pair of rotation pins connected through links to transmit driving power from a switching mechanism are used to transmit driving power for switching a circuit from the switching mechanism to single pole units, respectively, at the same time. Such a pair of rotation pins are formed lengthways to be connected through shafts at an inner portion of each single pole unit, and those shafts are supported to be rotatably driven by a rotation pin and revolved together with the movable contactor.
According to the configuration of such a four poles mold cased circuit breaker, referring to FIG. 6, the driving force imposed to a rotation axis 2a, 2b located at a portion of the N-pole single pole unit farthest away from the switching mechanism is weakened and the force imposed to a rotation axis 2a, 2b by a contact force between contacts is same, thereby causing deformation that the rotation axis 2a, 2b is bent in the direction of a force imposed to the rotation axis 2a, 2b by a contact force between contacts.
The deformation of such a rotation axis 2a, 2b causes switching operation failure of the N-pole single pole unit, and as a countermeasure to this, the applicant of the present invention has proposed a correction device with a rotation pin as disclosed in Korean Patent Registration No. 10-0689324 (Title of the Invention: Multi-poles mold cased circuit breaker)
The related art of the patent registration has a technical spirit that is configured with upper and lower blocks for inserting a rotation pin therebetween and a screw and a nut for pressing the upper and lower blocks to simply correct the deformation of a rotation pin by fastening a screw. However, it was a method of manually fastening a screw to make correction, thereby causing a problem that the relevant portion of a rotation pin may be over-deformed to act as a load preventing the contact between contacts and damage the upper and lower blocks when the screw fastening force is excessive, and the contact between contacts cannot be made or may be poor in the N-pole single pole unit when the screw fastening force is insufficient. In other words, the related art has a first problem that the correction amount is not uniform. Furthermore, the related art has a second problem that it may not be applicable when a space between the single pole units is narrow since it has a configuration in which the upper and lower blocks having a thickness and a screw and a nut are used.